H28 Datasheet, PDF (6/11 Pages) –

I²C SERIAL INTERFACE CONTROL
Serial Interface
H28 has two wire serial I²C bus type interface
comprising of serial clock (SCL) and serial data
(SDA) pins. I²C bus is used to write configuration
data to sensor interface IC and read the
measurement result when A/D conversion has been
finished.
Digital interface includes also master clock (MCLK),
end of conversion (EOC) and master reset (XCLR)
pins.
MLCK signal is needed to be clocked during
conversion period. It can be stopped after EOC goes
high which indicates that A/D conversion has
Device and Register Addresses
I²C bus standard makes it possible to connect
several I2C bus devices into same bus. The devices
are distinguished from each other by unique device
address codes. H28 device
Table 2. H28 device address
A7 A6 A5 A4 A3 A2 A1 W/R
1 1 1 0 1 1 1 0/1
H28 contains three 8-bit registers which are
presented in table 3. Control register is used to
configure the device to proper measurement setup.
Table 3. H28 internal register addresses
been accomplished. MCLK signal can also be
running all the time.
XCLR is used to reset the A/D converter. Reset
initializes internal registers and counters. After
connecting supply voltage to H28 and before starting
operating the device via I2C bus it is required to
reset the device with XCLR reset pin if supply
voltage rise time has been longer than 400 ns. If the
supply voltage rise time is shorter than this the
external reset with XCLR pin is unnecessary since
the device is automatically resetted by power on
reset (POR) circuitry.
address is shown in table 2. The LSB bit of the
device address defines whether the bus is
configured to Read (1) or Write (0) operation.
Control register bits are described in table 1 (page 4).
Two other 8-bit registers are used to store the 16-bit
A/D conversion result.
A7 A6 A5 A4 A3 A2 A1 A0 Register Description
1 1 1 1 1 1 0 1 MSB A/D Conversion Result Register
1 1 1 1 1 1 1 0 LSB A/D Conversion Result Register
1 1 1 1 1 1 1 1 Control register